Re: For those that use Ferber during naptime.
If my baby is really awake and playing I sometimes go and get her because she isn't ready to sleep yet. I keep her up and let her play for a bit and then put her back down when tired. If I know she's tired and she's tiredly babbling I won't go in. If she starts crying I wait about 5 mins (maybe a little less since it's been a longer time since she went down) from when the crying starts and then go in. If your baby is constantly playing, perhaps putting him down a little later for a nap might help.